git: 'resolve-reference' handles 'git describe'-style commit IDs.

* guix/git.scm (resolve-reference): Rewrite tag-or-commit case to recognize
'git describe' style identifiers and resolve them as commits.
* doc/guix.texi (origin Reference): Mention it.

1 files changed, 5 insertions, 4 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 29246ad4e5..f88967b593 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -47,7 +47,7 @@ Copyright @copyright{} 2017, 2018 Carlo Zancanaro@*
 Copyright @copyright{} 2017 Thomas Danckaert@*
 Copyright @copyright{} 2017 humanitiesNerd@*
 Copyright @copyright{} 2017, 2021 Christine Lemmer-Webber@*
-Copyright @copyright{} 2017, 2018, 2019, 2020 Marius Bakke@*
+Copyright @copyright{} 2017, 2018, 2019, 2020, 2021 Marius Bakke@*
 Copyright @copyright{} 2017, 2019, 2020 Hartmut Goebel@*
 Copyright @copyright{} 2017, 2019, 2020, 2021 Maxim Cournoyer@*
 Copyright @copyright{} 2017, 2018, 2019, 2020, 2021 Tobias Geerinckx-Rice@*
@@ -7010,9 +7010,10 @@ retrieve.
 The URL of the Git repository to clone.
 
 @item @code{commit}
-This string denotes either the commit to fetch (a hexadecimal string,
-either the full SHA1 commit or a ``short'' commit string; the latter is
-not recommended) or the tag to fetch.
+This string denotes either the commit to fetch (a hexadecimal string),
+or the tag to fetch.  You can also use a ``short'' commit ID or a
+@command{git describe} style identifier such as
+@code{v1.0.1-10-g58d7909c97}.
 
 @item @code{recursive?} (default: @code{#f})
 This Boolean indicates whether to recursively fetch Git sub-modules.